In an electric vehicle or the like, a large-capacity storage battery is required, and therefore, a battery assembly in which a large number of batteries are arranged and fixed is used. Further, as such a battery assembly, there has been proposed a battery assembly in which a plurality of batteries, arranged via battery holders made of resin, are fixed in a clamped manner from both sides by end plates made of resin or metal (see Patent Document 1 and Patent Document 2, for example).
The respective batteries of the foregoing battery assembly are arranged in such a manner that lateral surfaces of rectangular box type metal battery cases, each having the largest area, are opposed to each other, and battery holders made of resin are each placed between the adjacent batteries, thereby providing a laminated battery body. Furthermore, the end plates are placed outwardly of the batteries at ends of the laminated battery body, and the laminated battery body is fixed in a clamped manner by these end plates, thereby providing the battery assembly.
The battery holders serve to provide insulation between the batteries located on both sides of each battery holder and to form ventilation cooling passages between lateral surfaces of these batteries, each having the largest area, so as to cool each battery. Moreover, the battery holders hold portions of the lateral surfaces of the batteries, each having the largest area, in a fitting manner; thus, the battery holders function to facilitate assembly of the laminated battery body, and also function to prevent positional deviation or disconnection of the batteries from the laminated battery body fixed in a clamped manner by the end plates.
In this case, the end plates serve to fix a plurality of massive batteries in a clamped manner so as to provide the battery assembly, and also serve to attach the battery assembly to an installation position or the like; hence, when the end plates are made of a low-strength material such as resin, the thicknesses thereof must be sufficiently increased, and the volume efficiency of the resulting battery assembly is reduced, so that the thicknesses are preferably reduced with the use of the end plates made of metal having high strength. For example, in Patent Document 2, since end plates made of resin are used as illustrated in FIGS. 1 to 4, the thicknesses thereof are significantly increased, and the resulting battery assembly will occupy an excessive installation space.